Alkaline-earth silicid.



NITED" STATES PATENT OFFICE.

CHARLES E. J AOOBS, OF AMPERE, NEW JERSEY, ASSIGNOR TO THE AMPEREELECTROCHEMICAL COMPANY, OF SAME PLACE.

ALKALINE-EARTH SILICID.

SPECIFICATION forming part of Letters Patent No. 656,363, dated August21, 1900.

Application filed October 31, 1899. Serial No. 735,422- (No specimens.)

To all whom it may concern Be it known that 1, CHARLES E. JACOBS, acitizen of the United States, residing at Ampere, in the county ofEssex, in the State of New Jersey, have discoveredcertain new and usefulAlkaline-Earth Silicids, of which the following is a specification.

This invention relates to a new and useful chemical compound consistingof the silicid of an alkaline-earth metal-namely, calcium barium orstrontium silicid. These compounds, which have the formula OaSi BaSi andSrSi respectively, or generally-the formula Rsig, wherein R indicatesany alkaline-earth metal, are the silicon analogous'of thealkaline-earth carbids. I have discovered that when the carbonates,oxids, sulfates, or phosphates of the alkaline earths are mixed withsilica in the form of ground quartz or sand in which the relativeproportions of the alkaline-earth metal to the silicon in the mixture isas one is to two, and sulficient carbon to eifect the reduction isadded, or when silicates of the alkaline-earth metals in which therelation of the alkaline-earth metal to the silicon is as one is to twoare mixed with sufficient carbon to take up the oxygen of the compoundspresent and heated in the electric furnace under conditionssubstantially like those maintained in the manufacture of alkaline-earthcarbids, silicids of the alkaline-earth metals result.

As an example of the process, the following reactions for the formationof calcium silicid frpm the various calcium compounds are given:

(5) OaSiO +SiO +oOzGash-P500. Barium and strontium silicids are formedby exactly similar reaction from similar compounds.

The following description of the formation of calcium silicid from limeand sand is given as an example of the manner in which the manufactureof any of the alkalineearth silicids may be carried out. A differenceinthe relative weight of the mixtures will be necessary for oxids,carbonates, sulfates, phosphates, or silicates.

The type of electric furnace used may be any of those suitable for themanufacture of calcium carbid; but it ispreferred to use the continuousrotary fu rnace described inUnited States Letters Patent No. 597,945toBradley, January 25, 1898.

The charge consists of lime, fifty --six to sixty parts, by Weight,depending on purity; ground quartz or white sand, one hundred and twentyto one hundred and thirty parts, by Weight, depending on purity, andground coke or small anthracite, sixty to seventy parts, by weight,depending on purity. These are ground fine and thoroughly mixed and fedinto the furnace through which the current is passing by the ordinaryfeed device. The carbon acts on the oxygen of the charge, forming carbonmonoxid, and the calcium and silicon combine to form calcium silicid,which flows down or accumulates in the hearth of the furnace, when itsolidifies on cooling and is removed in the usual manner. In referenceto the products of this rcactionnamely, the silicids of calcium, barium,and strontium,(OaSi,, BaSi SrSi )these compounds, which are the siliconanalogues of the alkaline-earth carbids, are formed at the temperatureof the electric furnace when alkaline-earth compound and silica arereduced with carbon. They are white or bluishwhite substances ofmetallic appearance and also resembling aluminium silicid and siliconsomewhat in appearance. They possess a distinctly-crystalline fracture,showing platelike crystals very similar to those seen in the fracture ofcast-zinc, the crystals being, however, somewhat smaller in size. Theyoxidize slowly in the air and more rapidly under the influence of heat,yielding silicon dioxid and the oxid of the alkaline-earth metalspresent. Like the carbids, they decompose with water, but yield insteadof acetylene hydro= gen in a pure state, which is evolved Withoutexplosion, the following being the reaction:

The calcium compound decomposes slowly in cold water, but more rapidlyin hot water. The barium compound decomposes rapidly in both cold andhot water. The strontium compound decomposes more rapidly in water thanthe calcium, but not so-rapidl ygas the barium, compound. Itfw'ill benotice by considering the equations 1, 2, and 3 that all of thesecompounds evolve large volumes of hydrogen, one pound of OaSi producing.104 pounds, or 18. 73 cubic feet hydrogen, one pound of BaSi producing.051 pounds, or 9.15 cubic feet, and one pound of SrSigproducing .069pounds, or 12.36 cubic feet at 0 centigrade and seven hundred and sixtymillimeters. As hydrogen producers they offer a means of making bydrogen from water for use in gas-engines, and particularly for use ingas-engines on automobile vehicles, since the hydrogen is practicallypure, and all disagreeable odor and fume now so objectionable ingas-engines may be avoided.

The silicids decompose rapidly in dilute acids, the barium compoundgiving silica methane or silicon hydrid (SiH mixed with more orless freehydrogen, the reaction being similar to that which takes place whenmagnesium silicid is treated with dilute hydrochloric acid. Calciumsilicid, however, reacts in an entirely different manner when treatedwith dilute acids, either the oxy-acids or the hydrogen acids, and givesrise to the formation of a new compound, which has the formula Si H andis therefore the silicon analogue of acetylene (C H and must be calledsilico-acetyamass lene, since it bears the same relation tosilicomethane (silicon hydrid SiH as acetylene bears to methane (0H,.)It is a bright-yellow crystalline powder. The reaction which produces itis as follows:

This product Si H is more fully described and claimed in an applicationfiled January 12, 1899, Serial No. 1,180.

Strontium silicid when treated with dilute acids acts in a mannerintermediate between the actionof the barium compound and the calciumcompound, forming silicon hydrid, free hydrogen, and silico-acetylene.

Having thus described my invention, what I'claim as new, and desire tosecure by Letters Patent, isi 1. The chemical compound consisting ofsilicon combined withan alkaline-earth metal,

in the proportion represented by the formula RS5, R representing thealkaline-earth metal, the same being white or bluish-white substances ofmetallic appearance,having a crystalline fracture, oxidizing slowly inthe air to silicon dioxid and an alkaline-earth-metal A. P. KNIGHT, H.E. KNIGHT.

